Applied Research Of Arterial Spin Labeling In Diagnosis Of Craniocerebral Diseases

Objective:To study the performance of arterial spin labeling(ASL) in normal adult brain, acute and subacute cerebral infarction, transient ischemic attack, cerebral tumor and other intracranial diseases, so as to investigate the applied value of ASL in diagnosis of craniocerebral diseases.Methods:The following subjects were all examed with the Siemens Magnetom Trio Tim 3.0T magnetic resonance imaging scanner,1. 40 healthy volunteers were performed conventional T1WI, T2WI, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI) and the ASL sequence (Q2TIPS) examinations. To analysis the regional cerebral blood flow (rCBF) maps and quantitatively measure the blood flow value, so as to provide standard performance and values of cerebral blood flow perfusion in normal ASL imagings.2. 60 patients of ischemic cerebrovascular diseases (40 cases were clinically suspected to suffer from acute cerebral infarction, 20 cases were clinically suspected highly or diagnosed as transient ischemic attack) were performed conventional T1WI, T2WI, FLAIR, DWI and the ASL sequence examinations; 17 cases of acute cerebral infarction and 15 cases of TIA patients with MRA sequence examinations. To observe the regional cerebral blood flow (rCBF) maps and analysis changes in bilateral cerebral perfusion, to study the diagnostic advantages of ASL in ischemic cerebrovascular diseases; Combined with DWI imagings, to explore the diagnostic characteristics of ischemic penumbra.3. 19 patients of cerebral tumors were performed conventional T1WI, T2WI, FLAIR, CE-T1WI and ASL sequence examinations. To analysis the regional cerebral blood flow (rCBF) maps and to explore the diagnostic value of ASL in cerebral tumor compared to the performance of CE-T1WI images.4. 20 patients of other intracranial diseases were performed conventional T1WI, T2WI, FLAIR and ASL sequence examinations, 7 patients were performed DWI sequence examinations and 3 were performed CE-T1WI sequence examinations. To analysis the regional cerebral blood flow (rCBF) maps and to explore the diagnostic value of ASL .Results:1. Normal adult brain ASL techniques can clearly demonstrate cerebral blood flow distribution of gray matter, white matter and deep nuclei in healthy volunteers, the gray matter's blood flow was significantly higher than white matter's, the average CBF value of gray matter in bilateral cerebral hemisphere was(67.29±10.81) ml / (100g·min) and of white matter was(32.6±7.35) ml / (100g·min), the average CBF ratio of gray matter to white matter was 2.2±1.3.2. Ischemic cerebrovascular diseases The positive rates of showing lesions: With DWI sequence, there was 100% in acute and subacute cerebral infarction and 0% in TIA; With ASL sequence, there was 100% in acute and subacute cerebral infarction (ignoring 6 patients of acute cerebral infarction with badly imagings because of motion artifact) and 70% in TIA. The size of the same lesion in the same patient with DWI and ASL sequece: SDWISASL, n=0; DWI with negative results while ASL positive, n = 14 (TIA); DWI and ASL both with negative results, n = 6; DWI with positive results while ASL negative because of motion artifact, n = 6.3. Cerebral tumor High-grade malignant gliomas (WHOⅢ,Ⅳlevel) were significant hyper-perfusion compared to the contralateral normal cerebral tissues while low-grade gliomas(WHOⅡlevel) with lower rCBF and could be shown the uneven intratumoral blood flow distribution; Meningioma and hemangiopericytoma have higher rCBF values than normal brain tissues; Neuroblastoma showed hyper-perfusion performance and the hyper-perfusion area was larger than enhanced area in CE-T1WI imaging. Tumors with cystic and solid body had performance of mixing hyper- and hypo-perfusion.4. Other intracranial diseases ASL techniques used in cerebral abscess showed peripheral hyper-perfusion and central hypo-perfusion. ASL techniques can be used in patients with temporal lobe epilepsy for measuring temporal lobe blood flow and found that the anormal side's perfusion of 53.8% patients have a varying degree reduce compared to the contralateral normal temporal lobe; Compared with health subjects, the patients's total CBF values decreased. ASL images in neuronal migration abnormality showed slightly hypo-perfusion corresponding to the abnormal lesions.Conclusions:Arterial spin labeling technology, differ from conventional MR technologies which reflect to the changes of anatomical morphology, opens a unique channel of a non-invasive research of human brain function and physiology. ASL technology is one of MR perfusion imaging sequences with avantages of non-invasive, non-radioactive, easy accessibility to detect the cerebral blood flow. Our research information on the apply of ASL perfusion technology in craniocerebral diseases show a great application value. ASL techniques can be used to diagnose acute and subacute cerebral infarction and TIA in early stage, to prompt IP for combining with DWI sequence, to assess brain tumors'blood, to detect blood flow value of tumor, to predict preoperative grading of glioma, to assess blood supply of cerebral abscess lesions, to assess blood perfusion of temporal lobe in patients with temporal lobe epilepsy and blood flow abnormalities of neuronal migration abnormality, and so on. With maturity of the theory, improvement of the technology, development of the high-field equipment, the existence problems of ASL technology will be gradually resolved; In the future, ASL technology will make it possible to replace or partially replace the status of invasive techniques in assessment of cerebral blood flow.